To examine the social and economic impacts of the next Grand Solar Minimum – See About

Declining Solar Activity

BOB HOYE

In the 1990s, solar physicists, Penn and Livingston, called for a long decline in solar activity. This is the case and it is nice to see such work confirmed by events. Solar Cycles # 23 and 24 are the weakest since the early 1900s. The current run of consecutive Spotless Days is out to 33, or 75%, for the year.

[See Penn and Livingston paper and graphics below.]

The following table shows the record back to the minimum of Solar Cycle # 23 when the count was at 268 days, or 73%, for 2008.

So far this year, the count is out to 33 consecutive days, which is exceptional. So much so, that SILSO keeps a table of such long runs.

Solar Cycle # 24 is expected to reach its minimum by late in this year.

For hundreds of millions of years such changes in solar activity have been associated with changes from warming to cooling. And back again. The long run to the recent peak in activity was the strongest in thousands of years. Despite this, temperatures were not as warm for as long as set during the Medieval Warm Period. The end to that long trend and turn to cooling in the early 1300s was drastic, causing widespread crop failures and famine in Northern Europe and England. A book by William Rosen, “The Third Horseman” covers it thoroughly. The die-off from 1315 to 1320 is estimated at some 10 percent of the population. Deaths of cattle, sheep and horses were severe as well. All due to the turn to cold and unusually wet weather.

The change to what some are calling the Modern Minimum is significant. In geological perspective, it is now a built-in cooling force.

5 thoughts on “WUWT: Declining Solar Activity”

“For hundreds of millions of years such changes in solar activity have been associated with changes from warming to cooling. And back again. ”

Exactly how are solar activity records for “hundreds of millions of years” in the past being obtained? The actual observation record is only 400 years old. The cosmogenic proxies for solar activity only extend back through the Holocene. So…. what, specifically?